Fluid drive differential transmission



June 4, 1940. G. T. PoLLARD FLUID DRIVE DIFFERENTIAL TRANSMISSION Filed March 29, 1939 2 Sheets-Sheet 1 our - /NVENTops ff/wan Z' Faun/a By MM ATTO/:wey

Patented June 4, 1940 invention relates to anhautomatic automo-a.

`- tivetraiismission devie'eiand has forV its principal" :object-the provision ofga simple` vand efficient 'latrjansmission mechanism. which'.Y will-,autornativ, cally b'ringthespeed ratio from a'n'in-fntely'low4 'y gear ratioitoa direct drive., ratiofwithout requir-f' s nueA to vadvance these'4 A J Y speedrela onswtoanfoyerdrive so that the driven f shaft will'b ,rots'itedI nore'frapidly than the driv`e Iall these variable speed eration or fiow` of power.

20 -tivespeedldiiferences`intwo or more fluid drives and so` arijange'btherelative differences or varyt "injg slipjor gradual pcl-up as a slower or quicker clutching action and combining these in a useful 25grelation for automatic power transmission.` These useful relations are obtained either by the propor- "tional sizes ,ofv the parts, by regulating the fluid l densityof the ,liquids `orlby varying the distance fbetween-` the driving ordriven parts within the "fiuid`drive. f `A further object of this invention is to adapt a .transmission means to all intermediate speed rati'osof-"an automobileengine so that the results lf-torque"demand,andpower flow will be autofniaucanysupplied,without undue speeding of the enginaand its attendant waste of fuel. l Otherobjeet's 4and'ac lvantages reside in the de- .rtaii consumata-.of the invention, which is de- ;fsigned for simplicity, economy,` and eiiiciency. f These ,willf` become more apparent from the fol- A lowing` description.

.In thefollowing detailed description of the in- --ventionrference is had to the accompanying drawings-which form a part hereof. Like numer- `alsrefr-to like parts' in all views of the drawings and throughout the description.

,"LlFlg. 1 illustrates one formof the transmission 50 `deviceembodying'` only an underdrive ratio.

` Fig. 2 is a cross sectional view taken on the line 2.4, Fig; 1.: `Fig. 3" isla sectional view .through a second form of-theinvention extended to provide both under drive and overdrive ratlos.

Miss

nd then if the igad is `A fur-ther 'object'of-tlief invention is to use rela- PATIENT f OFFICE; i DiFFERENTIAL I i N. l v Gra'fr. Panam, pnvencql'e. s j .I."ifenialieauon Maren 29,1939,` serial, ne. 264,759

` f 'f s Claims." rc1. mfisasy s TRANS# s Fig.j5 is a 'similar crosssectionf taken the within afsuitabloil tight 4case I I.

invention is similar', andfeach-employsal-"drive shaft tu., In` an automotivefvenicle, tnegshaft I0 may lead' from a suitable/clutch loi'wconnectf L Yingthe .shaft IIJ`to the enginegfshaftj drive shaftIIlv extends into the oaseflljjthroug azdrive shaft bearing I2 and terminatesfiin, 'andE is keyed to, a driveV sun gear I3 whichisconstantly in,

mesh withfa series ofplanetgearsJL., The planet gears I4 are 'mounted'upon'suitable planet gear shafts I5 iii a rotary-planetfhousing I6` and are in constant mesh'with a-ffije'sun gear I1 formed or mountedyonfthe'jeiitremity` `of altubular shaft I8 surroundingthedrve shaft I0.` The other extremity of :the Jtubular shaft IB carries a fiuid housing I9. The`luid housing is sealed between the shaft I8' and the sh'aft I0 by means of suitable packing 20.

The housing I9 is formed` with a seriesof internal paddles 2|. A runner 22 ris keyed to the shaft I0 and extends into the'houslng; I9. The runner is provided with a series of baflies or paddles 23 which are in a closely spaced vrelation with the housing paddles 2|. `The housing I9 is sealed to a hub on the runner 22 by means of suitable packing 24 and a thrust bearing 25 is positioned to absorb the thrust between the` runner and the housing.

An external roller ratchet member 28 isformed or secured on the tubular shaft I8 so as to rotate within. an internal roller ratchet member 21 permanently fixed in the gear case' II. Suitable ratchet rollers 28 ride between the two ratchet members 26 and 21. The ratchet members are so faced as to prevent reverse rotation of the tubular shaft I8.

'Ihe tubular shaft is supported in suitable bearings 29 within the case II and the planet gear housing is similarly supported in bearings 30. The planet gear housing terminates in a power gear 3| for delivering the power from the automatic portion of the transmission. Y

A selective transmission, which maybe similar to those at present in usegmay be incorporated in the case I I. Such a transmission is illustrated in Fig. 1, wherein the power gear 3| is in constant mesh with a counter-shaft gear 32.011 a counter-shaft 33. The counter-shaft also carries an intermediate gear 34 and a reverse gear 35. The reverse gear 35 is in constant mesh with a reverse pinion 36.

A shifting gear 31 is splined upon a driven shaft 38 extending through shaft bearings 39 in the case. The inner face of the shifting gear is formed with a male clutcli boss 40 which can be brought into engagement with a female clutch socket 4I in the power gear. The other extremity of the shifting gear is formed with the usual shifting yoke groove 42 in which a shifting yoke 43 rides.

f It can be seen that when the shifting gear 31 is in the position of Fig. 1, the power from the power gear 3| will fiow through the gears 32, 34 and 31 to the driven shaft 38 driving the latter at reduced speed from the power gear 3l. If the shifting gear is shifted to the left, it will be directly connected to the power gear and if shifted to the right, it will engage the reverse pinion 36 to reverse the shaft 38,

Let us assume that the engine is idling, that the gear 31 is in the position of Fig. 1, and that the car clutch is brought to engaged position. The shaft I0 will immediately start rotation to the right to rotate the runner 22 and the sun gear I3 to the right, the load on the driven shaft will A hold the planet housing I6 stationary and the gear I3 will endeavor to act through the planet gears I4 to reverse the driven sun gear I1. It cannot reverse this gear, however, due to the fact that the ratchet rollers 28 prevent reverse rotation` of the shaft I8. f

Therefore, the vplanet gears will react against their shaft I3 to rotate the planet housing I6 forwardly at one-half speed. This one-half speed is transmitted through the intermediate gear 34 to the shaft 38 at still greater reduction of speed and, of course, increased power. The paddles 23 are now rotating with a forward thrust in the stationary fluid housing I9. As the speed of the shaft I0 increases, the reaction of the fluid in the housing will impinge the same against the paddles 2| tending to cause them to rotate in the forward direction with gradual acceleration. This rotates and accelerates the free sun gear I1 from a stationary position to a forward rotation. As the sun gear I1 begins to move'forward,

it will add its rotative effect to the rotative effect of the drive sun gear I3 on the planet gears I4 to cause the planet housing I6 to increase in forward speed, until a point is eventually reached when the runners 22 and the housing I9 are both rotating at substantially the same speedl when the planet housing I6 will be carried around as a unit with its planet gears and the power gear 3I will be rotating at a l-1 ratio with the shaft I0. The operator can now shift the yoke 43 to engage the clutch faces 40 and 4I. 'I'his immediately tends to slow the planet housing I6 and the fluid housing I9. 'Ihe reaction of the runner in the fluid in the housing, however will cause the housing to again gradually pick up forward speed until it is again rotating in substantial synchronisn/i/ with the runner 22 to` place the shafts Ill and 38 again in a 1-1 ratio. v

At any time that the load on the shaft 38 increases, sufficiently to overload the shaft Il), the reaction will tend to cause the free sun gear I1 to slow down and as it reduces its speed, it gradually decreases the speed ratio between the shafts I0 and 38. If this load still further increases, the free sun gear will come to rest so that the power gear 3| and the shaft I0 will be placed in a 1 to 1/2 ratio to pick up the load. As before stated, in -this form of the invention; the sun gear I1 cannot reverse to bring the ratio belowr 1 to l/2. L Overdrive orm In Fig. 3, a construction is illustrated whereby the same principles of operation are carried forward to provide an automatic overdrive as well as the above underdrive between the drive and driven shafts, and to provide still' lower under. drive gear ratios.

In this form, the drive shaft is indicated at 44 terminating in a drive sun gear 45 which drives a free sun gear 45 through the medium of planet gears 41 in a planet housing 48.

In this form, also, the free sun gear 46 drives a iiuid housing 49 by means of a tubular shaft 50 and the shaft 44 drives a runner 5I within the housing as in the previous form. In this form, however, the initial low ratio of 1-1/2 can be decreased to 1-0 so that the shaft 44 may initially rotate without imparting any rotation to the planet gear housing 48. This is accomplished by placing an external roller ratchet member 52 on the tubular shaft which acts through ratchet rollers 53 against a rotatable, internal ratchet member 54.

The rearward rotation of the ratchet member 5,4 can be retarded or retracted by means of a brake band 55 actuated through any suitable brake lever 56.

Operation of underdrve Let us assume the shaft 44 is rotating forwardly with the engine idling. The planet gear housing 48 is held against rotation by the load of the car and the power is flowing through the planet gears to the free sun gear 46 causing it to rotate in a reverse direction. This causes the ratchet member 52 and the housing 49 to rotate reversely while the runner 5I is rotating forwardly. g

Now let us assume that the brake lever 56 is operated to tighten the band 55. This gradually brings the outer ratchet member 54 to a stop and through the rollers 52 brings the tubular shaft 50 to a stop. This forces the planet gear housing to rotate forwardly at one-half speed. The reaction of the fluid in the housing will now gradually cause the latter to pick up speed until the 1-1 ratio has been reached as in the previous form. Therefore, in this form of the invention we have a ratio of from 1-0 to 1-1.

It will be noted that even though the brake band be not tightened, the\ positive forward rotation of the runner will gradually bring the fluid housing to rest and then start to gradually accelerate it in a forward direction to the 1-1 ratio.

Overdrive construction To obtain the overdrive, the planet housing 48 is connected directly to a second planet housing 51 carrying similar planet gears 58 which are in constant mesh with a driven sun gear 59 and a free sun gear 60. The driven sun gear 59 is fixed on the extremity of a driven shaft 6I. The sun gear 60 is connected through a ratchet housing 62 to a second fluid housing 63. The shaft 6I carries an internal ratchet member 64 acting through ratchet rollers 65 against the ratchet housing 62. -This ratchet prevents the sunrgear 60 from exceeding the speed of the sun gear 59 for as soon as the ratchet housing tends to rotate faster than the ratchet 64, the rollers-will lock the two together.l This ratchetl arrangement, however, allows the floating sun gear 6I to reverse in direction from that of the gear 59 without lnterference.

The second fluid housing 63 contains a runner 66 which is connected directly to a runner gear 61. The runner gear 51 isin constant mesh with a first counter-shaft gear 6B on a counter-shaft $9 which also carries a second counter-shaft and intermediate gear 10. The latter gear drives a fixed shaft gear 1I through the medium of a reverse pinion 12. A shifting gear 13 is splined on a power shaft 1I so that it may be brought either into mesh with a reverse gear 15 or into direct connection with the driven shaft 6I by means of clutch faces 15.

The gear 13 may be shifted through any of the usual shifting yoke levers 11 to three positions, a neutral position. N, a reverse position R., if moved to the right. and a forward position F if moved to the left, as illustrated in Fig. 3.

'I'he gears 13 and 15 are simply for accomplishing reverse rotation ofthe shaft 14 at all of the ratios of the transmission.

The second fluid drive, Bil-66, is arranged so that it will have a lower transmission efficiency than the first fluid drive, lil-5i. so that in case of an overload it will slip before the first fluid drive does. This can be accomplished in any desired way, such as by having a lighter oil; having less or smaller paddles: or by greater spacing between the housing and the runner.

Operation of overdrive Let us assume that the clutch faces 16 are engaged and the planet housing 48 is rotating forwardlyl at the same speed as the shaft M. This forward rotation, of course, is carried to the second planet housing 51 causing the planet gears 58 to endeavor to rotate both of the sun gears 59 and 60 forwardly.

The load on the gear 59, however, tends tol cause the planet gears 58 to speed up the gear 60. This gear. however, cannot increase in speed over the gear 59, due to the ratchet rollers 65, and the driven shaft initially rotates at a ratio of l-l, with the planet housing 51.

The second fluid housing 63 is also rotating forwardly since it is fixed to gear 60. The shaft 6I through the gears .1I, 12, 1U, 68 and 61 rotates the latter gear in a reverse direction causing the runner 6B to rotate in a reverse direction in the housing 63.

The reaction of the fluid in the second housing 63 gradually imparts this reverse rotation to the housing, reversing the direction of the sun gear 60 to full rotation in a reverse direction with reference to the shaft 6I and driven sun gear 59. The sun gear GO now transmits power through the planet gears 58 to theasun gear 59 causing the latter to rotate proportionally and gradually faster until the shaft 61 will finally have added rotation forwardly at a 1-2 ratio with the planet housing 51. The second fluid overdrive action to take place after the first fluid underdrive has reached its full drive relation of 1-1 ratio.

It will be noted that the entire operation is automatic, the torque delivered by the power shaft is in proportion to the load applied thereon and the relative speed of the power shaft increases inversely to the load. The brake band 55 and the reverse ratchets of the underdrive simply accelerate the pick-up through the lowest ratios but neednot be used if complete automatic operation is desired.

While a specific form of the improvement has `been described and illustrated herein, it is desired to be understood that the same may be varied, within the scope of the appended claims, without departing from the spirit of the invention.

Having. thus described the invention, what Vis claimed and desired secured by Letters Patent is: l. An automatic power transmission device comprising: n driven member; planet gears supported from said driven member about its axis: a ,driven sun gear in constant mesh with said planet gears; a driven shaft secured to said driven sun gear; a free sun gear concentric with said shaft and in constant mesh with said planet gears; a two element slipping transmission device, one element thereof being fixed to said free sun gear; and means for driving the other element thereof from saiddriven shaft in a reverse direction relative to the rotation of said driven shaft.

2. An automatic power transmission device comprising: a driven member; planet gears supported from said driven member about its axis; a driven sun gear in constant mesh with said planet gears; a driven shaft secured to said driven sun gear; a free sun gear concentric with said shaft and in constant mesh with said planet gears; a two element slipping transmission device, one element thereof being xed to said free sun gear; a tubular shaft surrounding said driven shaft, the other element of said transmission device being carried by said tubular shaft; and power transmission means between said driven shaft and said tubular Shaft to rotate the latter relatively opposite from the former.

3. An automatic power transmission device comprising: a driven member; planet gears supported from said driven member about its axis; a driven sun gear in constant mesh with said planet gears; a driven shaft secured to said driven sun gear; a free sun gear concentric with said shaft and in constant mesh with said planet gears; a two element slipping transmission device, one element thereof being fixed to said free sun gear; means for driving the other element thereof from said driven shaft in a reverse direction relative to the rotation of said driven shaft; and directional clutch means between said driven shaft and said free sun gear so positioned as to prevent the latter from rotating at a higher speed than the former.

4. An automatic power transmission device comprising: a driven member; planet gears supported from said driven member about its axis; a driven sun gear in constant mesh with said planet gears; a driven shaft secured to said driven sun gear; afree sun gear concentric with said shaft and in constant mesh with said planet gears; a fluid housing rotated from said free sun gear; a runner inJtsaid fiuid housing; and means for rotating saidrunner from said driven shaft in a direction opposite to the rotation of said driven sun gear.

5. An automatic power transmission device comprising: a driven member; planet gears supported from said driven member about its axis; a driven sun gear in constant mesh with said planet gears; a driven shaft secured to said driv en sun gear; a free sun gear concentric with said shaft and in constant mesh with said planet gears; a fluid housing rotated from said free sun gear; a runner in said uid housing; means for rotating said runner from vsaid driven shaft in a direction opposite to the rotation of said driven sun gear; and directional clutching means positioned to prevent said fluid housing from rotating faster than said driven sun gear.

6. An automatic, ratio-changing, power transmission device comprising: a power shaft; a planet support surrounding said power shaft: means for receiving the rotative effort oi' said planet support: planet gears in said planet support; a driven sun gear flxed'on said power shaft in constant mesh with said planet gears;a second sun gear in constant mesh with said planet gears; slipping transmission means between said drive sun gear and said second sun gear constantly urging the latter to rotate with the former; va directional clutch positioned to prevent said sec- 9nd sun gear from rotating reversely to said drive sun gear; and means for bringing said directional clutch into or out oi' its operative position.

7. In a planetary transmission of the type having a series of planet gears and means for revolving said series about the axis 0f, and in mesh with, a free sun gear and a driven sun gear, means for causing said driven sun gear to` turn faster than said planet gears revolve comprising: a uid transmission mechanism interposed betweenthe two sun gears; and means for transmitting the rotation of the driven sun gear to said mechanism in a reverse direction so that said mechanism will urge said free sun gear to rotate in a direction opposite to the direction of revolution of said planet gears.

8. A fluid drive transmission comprising: a planet support; means foi rotating said planet support; an annular series of planet gears carried by said support: a driven shaft supported coaxially of said series; a driven sun gear mounted on said shaft in constant mesh with said planet gears; a free sun gear rotatably mounted about said shaft in constant mesh with said planet gears; a directional clutch between said free sun gear and said shaft positioned to prevent the free sun gear from turning faster than the shaft but allowing reverse rotation of the former on said shaft; a two element fluid transmission device axially positioned about said shait, one element thereof being connected directly to said free sun gear; and means for transmitting the rotation of the driven shaft to the other element of said device in a direction opposite to the direction 0f rotation of said driven gear so that said device will urge said free sun gear to rotate oppositely to the direction of rotation of said planet Support.

GURDON T. POLLARD. 

